This invention relates to an improved method for filtering Bacillus subtilis or gene-recombinated Bacillus thereof.
Bacillus subtilis is well-known as a kind of rod-shaped bacteria which have no bad effect on a human being. Bacillus subtilis is also used as host bacteria for genetic engineering from the viewpoint that Bacillus subtilis can easily excrete metabolite whereby recombinant gene products can be obtained.
In order to obtain recombinant gene products at a high efficiency, a culture solution including Bacillus subtilis or gene-recombinated Bacillus thereof in a culture container is forced to pass through a pipe-like filter so as to be filtered in a cross flow manner. Thus, only the metabolite is filtered or removed while the enriched solution is sent back to the culture container. The metabolite can be continuously produced.
A conventional preferred example of the filter as above-stated is a ceramic filter because:
(1) it is not stained; PA1 (2) it is not solved out; PA1 (3) it is not broken in filtration; and PA1 (4) it can be disinfected by steam.
However, in case of the conventional ceramic filters, Bacillus subtilis is often disrupted during the cross-flow filtration because Bacillus subtilis is very weak. Such a problem mainly depends on characteristics of a ceramic filter to be used and filtration conditions.